Confinement of Skyrmion states in noncentrosymmetric magnets

TL;DR

This paper explores how Skyrmion states in noncentrosymmetric magnets become confined near the ordering temperature, forming bound states and unique lattice structures due to temperature-dependent interactions.

Contribution

It reveals the temperature-dependent transition from repulsive to attractive Skyrmion interactions and identifies confinement effects and precursor states near the transition.

Findings

Skyrmion interactions switch from repulsive to attractive at high temperatures.

Skyrmions exist only as bound states near the ordering temperature.

Skyrmion lattices form via an instability-type nucleation transition.

Abstract

Skyrmionic states in noncentrosymmetric magnets with Lifshitz invariants are investigated within the phenomenological Dzyaloshinskii model. The interaction between the chiral Skyrmions, being repulsive in a broad temperature range, changes into attraction at high temperatures. This leads to a remarkable confinement effect: near the ordering temperature Skyrmions exist only as bound states, and Skyrmion lattices are formed by an unusual instability-type nucleation transition. Numerical investigations on two-dimensional models demonstrate the confinement and the occurrence of different Skyrmion lattice precursor states near the ordering transition that can become thermodynamically stable by anisotropy or longitudinal softness in cubic helimagnets.